Field of Invention
The present invention relates to an image processing apparatus implemented in an image forming apparatus.
Description of Related Art
Heretofore, electrophotographic image forming apparatuses are known as multi-function printer (MFP) which incorporates the functionality of multiple devices such as printers, copying machines and so forth. This type of image forming apparatus performs calibration to adjust characteristics of the image forming apparatus for the purpose of realizing optimal color reproducibility. The calibration is a process of updating the gradation characteristics including densities and the like of respective colors, i.e., C (cyan), M (magenta), Y (yellow) and K (black).
When performing calibration, a plurality of patches having different densities are used. The patch is an image formed on a sheet for use in measuring and correcting colors and optically read by a line sensor consisting of imaging devices arranged in a line.
However, depending upon the optical system, flare may be reflected on the patch. Accordingly, when the patch is greatly influenced by flare, the read value of the patch deviates from the correct value. It is considered as one of the causes of such flare generation that light reflected around the patch becomes stray light.
This can be solved, for example, by storing the flare amount when a predetermined pattern is output and compensating flare by the use of the stored flare amount (for example, refer to Japanese Patent Published Application No. 2011-191918). In accordance with the technique described in Japanese Patent Published Application No. 2011-191918, the stored flare amount is referred to in order to compensate flare disturbing the image data which is input. By this configuration, image data can be generated without influence of flare.
On the other hand, in the case where a color patch for color measurement and correction is located in the blank space bordering the printed area in which is printed user content which is changed for each printing, it cannot be estimated how much flare influences.
However, in accordance with the technique described in Japanese Patent Published Application No. 2011-191918, flare is compensated based on the flare amount obtained from the predetermined pattern. Accordingly, appropriate compensation cannot be conducted even if flare is compensated based on the flare amount obtained from the predetermined pattern. This prior art may thereby not be used to compensate influence of flare with a high degree of accuracy.
The present invention is made in order to solve such a prior art problem and used to provide an image processing apparatus capable of compensating a flare component with a high degree of accuracy.